Epidemiological Study: Water Identified As Major Source Of Teflon Chemical Contamination
The blood of residents of a four-community region of southeastern Ohio contain levels of a chemical used to produce Teflon more than 60 to 80 times higher than those typically found in the general population, according to the nation's first government-sponsored epidemiological study of the chemical in the residents. The research team concluded that water is the major source of contamination.
The study -- which is independent of any corporation, law firm, or class-action suit -- is funded through a four-year Environmental Justice Partnership grant from the National Institute of Environmental Health Sciences; and is specifically designed as a collaborative initiative among environmental health scientists at University of Pennsylvania (Penn) School of Medicine, the Decatur Community Association in Cutler, Ohio, and a local physician affiliated with Grand Central Family Medicine in Parkersburg, W.Va.
The objectives of the study were threefold: to measure the levels of C8 in the blood of a sample of the population exposed to C8; to determine whether the major route of exposure is from air, water, or a combination; and to determine if the levels of C8 are associated with adverse changes in biomarkers of health effects. The researchers are continuing their analysis of the data related to the third objective.
C8 is the commonly used name for ammonium perfluorooctanoate (or PFOA). PFOA is perfluorooctanoic acid. It is a synthetic (man-made) chemical and does not occur naturally in the environment. The "PFOA" acronym is used to indicate not only perfluorooctanoic acid itself, but also its principal salts, according to EPA. The most commonly used chemical in this grouping is the ammonium salt, or C8.
C8 a chemical used in the production of fluoropolymers, which are used to make non-stick surfaces for cookware and other uses; as well as to make clothing, carpeting, and other products resistant to grease, water, and stains. According to manufacturers, C8 is not present in the final products. C8 is very persistent in the environment and is not biograded. Once inside the human body, it is very slowly eliminated.
The potential impacts of C8 on public health are still under investigation. Exposure to high concentrations of C8 over long durations has been shown to cause tumors in some test animals. It is not certain that C8 would cause the same effects in humans. Epidemiologic studies of occupational groups have not found consistent associations between C8 and health effects, but concerns about toxicity to human populations persist. According to EPA, the source of the C8 found in the general population is unknown at this time.
For the Penn study, a random sample of 326 residents was selected from 160 households in four communities in southeastern Ohio: Belpre; Little Hocking; Cutler; and Vincent. All four communities are situated across the Ohio River from a facility where C8 is used in the manufacture of Teflon(r). C8 is known to have contaminated the residential water supplies of communities near the plant. Parts of Little Hocking and Belpre are immediately across the river from the plant and could be subject to air pollution from the plant. Cutler & Vincent are some miles from the plant and would not be expected to have exposure to air pollution from the plant. However, all four communities share the same water supply.
The average level of C8 in the general population is approximately 5 parts per billion (ppb). The study showed that, when analyzed by specific geographical area, the median (or middle) C8 levels for participants with mailing addresses in Belpre was 298 ppb; Little Hocking, 327 ppb; Cutler, 328 ppb; and Vincent, 369 ppb. As part of the researchers' commitment to the community participants, letters have been mailed already to study participants to inform them privately of their individual blood-levels of C8.
"Our results show that the median levels recorded in participants in the study were from 60 to 80 times higher than general-population levels," said researcher Edward A. Emmett, MD, professor of Occupational & Environmental Medicine at Penn's School of Medicine. "In addition, increased levels were found in both sexes and all age groups, including children and the elderly."
"The C8 levels were high in all four communities, with no significant contribution from air pollution," noted Emmett. "As a result, we have concluded that the major source of the C8 in the residents' bodies is the contaminated water supply."
Residents who reported occupational exposure from working with C8 to a significant extent were excluded from the study's analysis (i.e., those employed by the nearby chemical plant for greater than one year and within the past 10 years). However, even with the elimination of this population subgroup, the researchers observed C8 levels in some study participants that approached -- and, in some cases, overlapped -- C8 levels reported in some earlier studies of individuals who work directly with C8.
Emmett said that appropriate health, environment, and water authorities for the affected study population have been notified of the preliminary results of the Penn study.
Additional information about PFOA can be found at http://www.epa.gov/opptintr/pfoa.
This article originally appeared in the 07/01/2005 issue of Environmental Protection.